Image forming apparatuses, e.g., printers, facsimiles and copiers include multiple rotators such as photoreceptors and developing rollers that are rotated to form images.
Japanese published unexamined application No. 2003-295552 (JP-2003-295552-A) discloses a drive transmitter including a first drive transmitting part including a dive gear mounted on a motor shaft and a photoreceptor gear engaged with the drive gear to transmit a drive force to the photoreceptor, a second drive transmitting part transmitting a drive force from the same drive motor as that of the photoreceptor to a registration roller and a fixing roller through a drive gear train formed of multiple gears, and a third transmitter transmitting a drive force from the same drive motor as that of the photoreceptor to a developing roller through a drive gear train formed of multiple gears.
In this drive transmitter, a thin-teeth gear, which is part of the drive gear train of the second drive transmitting part, is fixed to the same rotation shaft to which the photoreceptor gear is fixed. Thus, a projected area of the photoreceptor gear in an axial direction (overlapping the photoreceptor gear when axially seen) can effectively be used, and the drive transmitter can be downsized.
However, a rotation load of the fixing roller and the registration roller is also transmitted thereto, resulting in possible speed variation of the photoreceptor.